求取圆形区域内的平均灰度值

#include <cmath>
#include <opencv2/opencv.hpp>
using namespace cv;
using namespace std;

const int kvalue = 15;//双边滤波邻域大小
const double PI = 3.14;//圆周率

int graylevel(Mat image, Mat dst, Point cen, int r)//求取圆形区域内的平均灰度值
{
	int graysum = 0, n = 0;

	for(int i = (cen.y - r); i <= (cen.y + r); ++i)//访问矩形框内的像素值
	{
		uchar* data = image.ptr<uchar>(i);
		for(int j = (cen.x - r); j <= (cen.x + r); ++j)
		{
			double d = (i-cen.y)*(i-cen.y) + (j-cen.x)*(j-cen.x);
			if(d < r*r)
			{
				++n;
				graysum += (int)data[j];
			}
		}
	}

	for(int i = (cen.y - r); i <= (cen.y + r); ++i)//画出圆，圆内像素值为平均灰度值
	{
		uchar* temp = dst.ptr<uchar>(i);
		for(int j = (cen.x - r); j <= (cen.x + r); ++j)
		{
			double d = (i-cen.y)*(i-cen.y) + (j-cen.x)*(j-cen.x);
			if(d < r*r)
			{
				temp[j] =